It will be screened live on BT Sport following their coverage of Dundee v Inverness Caledonian Thistle, kick-off 3.00pm.
European entrants Celtic, Rangers, Kilmarnock and Aberdeen will be seeded in the draw, along with the four group winners with the best records.
If clubs are level on points at the end of the group stage the criteria for separating them is:
1) goal difference
2) goals scored
3) away goals scored
4) matches won
5) away matches won
6) drawing of lots
Last-16 ties are due to be played on the weekend of August 17/18 and are subject to TV selections.